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Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in the blocks＇ glass transition temperatures

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Frontiers of Chemical Science and Engineering 2017年第3期11卷 440-447页

作者： Yang Zhou phillip Choi Department of Chemical and Materials Engineering University of Alberta Edmonton Edmonton AB T6G 1H9 Canada

Isothermal-isobaric molecular dynamics simu- lation was used to study the diffusion mechanism of water in polyurethane-block-poly（N-isopropyl acrylamide）（PU- block-PNIPAm） with a hydrophobic PU/hydrophilic PNIPAm mass ratio of 1.4 to 1 at 298 K and 450 K. Here, the experimental glass transition temperature （Tg） of PU is 243 K while that of PNIPAm is 383 K. Different amounts of water up to 15 wt-% were added to PU-block- PNIPAm. We were able to reproduce the specific volumes and glass transition temperatures （250 K and 390 K） of PU- block-PNIPAm. The computed self-diffusion coefficient of water increased exponentially with increasing water concentration at both temperatures （i.e., following the free volume model of Fujita）. It suggested that water diffusion in PU-block-PNIPAm depends only on its fractional free volume despite the free volume inhomo- geneity. It is noted that at 298 K, PU is rubbery while PNIPAm is glassy. Regardless of temperature, radial distribution functions showed that water formed clusters with sizes in the range of 0.2-0.4 nm in PU-block- PNIPAm. At low water concentrations, more clusters were found in the PU domain but at high water concentrations, more in the PNIPAm domain. It is believed that water molecules diffuse as clusters rather than as individual molecules.

关键词： molecular dynamics simulation amphiphilic block copolymer free volume water diffusivity fujita model

Opportunities and challenges for a Golden Age of chemical engineering

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Frontiers of Chemical Science and Engineering 2014年第1期8卷 1-7页

作者： phillip R. WESTMORELAND Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh North Carolina 27695-7905 USA

Chemical engineering is entering a new Golden Age of practice, thought, and impact, accompanied by great new opportunities and challenges. Five aspects mark this development： a new abundance of hydrocarbons; the evolution of biology into a molecular science; the ubiquity of powerful computational tools; the trend in manufacturing to be more process-oriented; and the systems approach that is part of ChE education from its first stages. There are important technical challenges, including technology creation and environmental impact, but just as important are new appreciation for and attention to challenges that require societal dialogues about com- plexity, uncertainty, and evolving and sometimes contra- dictory requirements. Crucial to all these impacts is enhancing the identity of what the profession is. That must be based on recognizing that the core of chemical engineering is applying molecular sciences to create value and advance the quality of life.

关键词： hydrocarbons biotechnology computation,cyberinfrastructure manufacturing environmental

Depression, anxiety, and cardiac morbidity outcomes after coronary artery bypass surgery： a contemporary and practical review

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Journal of Geriatric Cardiology 2012年第2期9卷 197-208页

作者： phillip J Tully Robert A Baker Department of Surgery Flinders Medical Centre and Flinders University of South Australia 3 Flinders Drive Bedford Park SA 5042 Australia School of Psychology University of Adelaide Hughes Building North Terrace Adelaide SA 5005 Australia Discipline of Psychiatry The University of Adelaide Eleanor Harold Building Frome Road Adelaide SA 5005 Australia Heart Failure Self Management Program Ambulatory and Primary Healthcare Directorate Hampstead Rehabilitation Centre 207 Hampstead Road Northfield SA 5085 Australia

Research to date indicates that the number of coronary artery bypass graft （CABG） surgery patients affected by depression （i.e., major, minor, dysthymia） approximates between 30% and 40% of all cases. A longstanding empirical interest on psychosocial factors in CABG surgery patients highlights an association with increased risk of morbidity in the short and longer term. Recent evidence suggests that both depression and anxiety increase the risk for mortality and morbidity after CABG surgery independent of medical factors, although the behavioral and biological mechanisms are poorly understood. Though neither depression nor anxiety seem to markedly affect neuropsy- chological dysfunction, depression confers a risk for incident delirium. Following a comprehensive overview of recent literature, practical advice is described for clinicians taking into consideration possible screening aids to improve recognition of anxiety and depression among CABG surgery patients. An overview of contemporary interventions and randomized, controlled trials are described, along with suggestions for future CABG surgery research.

关键词： Depression Depressive disorder Coronary artery bypass Coronary artery disease Antidepressive agents Anxiety

Development of a Long-Term Operational Optimization Model for a Building Energy System Supplied by a Geothermal Field

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Journal of Thermal Science 2022年第5期31卷 1293-1301页

作者： KÜMPEL Alexander STOFFEL phillip MÜLLER Dirk RWTH Aachen University E.ON Energy Research CenterInstitute for Energy Efficient Buildings and Indoor ClimateAachen 52074Germany

In order to reduce energy consumption and CO_(2) emissions in the building sector, more and more renewable energy sources are integrated into energy systems. Especially geothermal fields combined with heat pumps are able to supply buildings with heat and cold at low carbon emissions. However, using geothermal fields as heat and cold source influences the ground temperature. Consequently, the ground temperature can change dramatically over a building’s lifetime, leading to less efficient operation of the energy system. Therefore, a sustainable operation is required to ensure the long-term efficiency of geothermal fields. In this paper, we develop an optimization model to derive operating strategies for an efficient long-term operation of a building energy system coupled to a geothermal field. The investigated energy system is the main building of the *** Energy Research Center in Aachen, Germany, which includes a heat pump, two boilers, a combined heat, and power unit, a glycol cooler, and a geothermal field with 41 probes. For each component, we develop energy-based sub-models, which are connected to form the overall system. The geothermal field is modeled by using a g-functions approach as well as a simplified resistance-capacitance approach. To achieve short computing times and realize an optimization horizon of several years, the optimization problem is formulated as mixed-integer linear programming(MILP). The developed model is optimized regarding two different objectives: the minimization of energy costs and the minimization of long-term temperature changes in the ground. Conclusions for an efficient and sustainable operation of the field, especially for the cooling supply, can be derived from the optimization results. It is shown that a state of equilibrium should be aimed to achieve an energy-efficient operation, in which the temperature of the field is close to the initial ground temperature.

关键词： geothermal energy building energy systems operational optimization long-term operation

Cloud-Based Optimal Control of Individual Borehole Heat Exchangers in a Geothermal Field

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Journal of Thermal Science 2022年第5期31卷 1253-1265页

作者： STOFFEL phillip KÜMPEL Alexander MÜLLER Dirk RWTH Aachen University E.ON Energy Research CenterInstitute for Energy Efficient Buildings and Indoor Climate52074 AachenGermany

Integrating renewable energy sources is a crucial component in reducing CO_(2) emissions in the building sector. In particular, shallow geothermal energy is expected to play a significant role in the regenerative energy supply of buildings. An effective control strategy for the geothermal field is crucial to reduce the overall energy consumption. This paper analyzes the benefits of controlling an existing field’s individual borehole heat exchangers(BHE) using nonlinear model predictive control(NMPC) and moving horizon estimation. The considered geothermal field consists of 41 BHEs and is used for heating and cooling. Each BHE is equipped with temperature sensors for in-and outflow and has individually controllable valves, while a central hydraulic pump feeds all BHEs. The sensor measurements are accessed through a cloud platform, enabling also set point writing for the pump speed and the valve positions. To control the BHEs individually, we propose a two-stage process. In the calibration stage, a moving horizon estimator estimates the actual borehole and ground temperatures for each BHE. In the second stage, first, a nonlinear model predictive controller optimizes the number of active BHEs necessary to meet the buildings’ energy demand. With the estimated ground temperatures as a basis, it is determined which BHEs shall be(de)-activated. The active BHEs are fed with a fixed volume flow of 24 L/min to ensure turbulent heat transfer. To reduce the power usage of the pumps, an optimal control problem based on a simple hydraulic model of the geothermal field is used. The methodology is analyzed through simulations first and then validated experimentally. The results show that half or more of the BHEs could be deactivated most of the time, leading to 67% savings in electricity consumption by the hydraulic pump. The experimental validation confirms the high energy saving potential of the proposed methodology, reducing the consumption of electrical energy by 71%. Additiona

关键词： geothermal energy moving horizon estimation model predictive control operation optimization optimal control

From bench to bedside： bipolar androgen therapy in a pilot clinical study

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Asian Journal of Andrology 2015年第5期17卷 767-768页

作者： Qing Zhang phillip J Gray Department of Internal Medicine Singapore General Hospital Singapore Department of RadiationOncology Massachusetts General Hospital HarvardMedical School Boston MA USA

Prostate cancer remains a leading cause of cancer death in Europe andthe United States and is an emerging problem in Asia despite significant improvements in available treatments over the last few decades. Androgen deprivation therapy （ADT） has been the core treatment of advance-staged disease since the discovery of prostate cancer＇s androgen dependence in 1941 by Huggins et al. Options for initial medical treatment include gonadotropin-releasing hormone analogues such as leuprolide （LHRH agonist） and degarelix （LHRH antagonist） and androgen receptor （AR） binding agents such as bicalutamide. Although most patients will initially respond to either surgical or medical castration, there is almost always progression to castration-resistant prostate cancer （CRPC） necessitating treatment with more novel agents. However, even drugs such as abiraterone and enzalutamide, two next-generation agents used commonly in metastatic CRPC, have failed to demonstrate persistent efficacy in most patients.

关键词： advance-staged next-generation bicalutamide

Temperature-dependent development of Xyleborus fornicatus （Coleoptera： Scolytidae）, the shot-hole borer of tea in Sri Lanka： Implications for distribution and abundance

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Insect Science 2007年第4期14卷 301-308页

作者： RAVINDRA SAMPATH WALGAMA MYRON phillip ZALUCKI SchoolofIntegrativeBiology UniversityofQueenslandSt.LuciaQueensland4072Australia

The effect of temperature on the rate of development of Xyleborus fornicatus （Eichh.） was determined by rearing individuals under a range of constant temperatures （15 - 32℃）. Rates of development changed in a linear fashion over a wide range of temperatures. Estimates of lower development thresholds were obtained for eggs （15.7±0.5℃）, larvae （15.8±0.8℃） and pupae （14.3±1.4℃） and the degree days （DD） for development were 70±4.4, 95±8.5 and 72±5.1 DD, respectively. Optimum temperature for development was around 30~C for all stages. Temperature fluctuation in cooler High Country areas （above 1400 m） with a mean temperature around 15℃ seems to be critical for the development of the pest, which may be responsible for the near absence of pest in those areas. Temperature fluctuations （18- 30℃） in the Mid Country region （600- 1200 m） favor the development of the pest compared to development under constant conditions. The altitudinal distribution of the shot-hole borer across tea growing areas in Sri Lanka is, therefore, mainly governed by temperature.

关键词： damage levels degree-days developmental thresholds tea growing regions

Public Risk Perception Attitude and Information-Seeking Efficacy on Floods:A Formative Study for Disaster Preparation Campaigns and Policies

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International Journal of Disaster Risk Science 2020年第5期11卷 592-601页

作者： Do Kyun David Kim T.phillip Madison Department of Communication University of Louisiana at LafayetteLafayette.LA 70503USA

Floods are among the most frequent and devastating natural hazards and disasters in many southern states in the United *** study examined the relationship and reciprocal predictability between two theoretical constructs-risk perception attitude(RPA)and informationseeking efficacy(ISE)——in regard to pluvial *** addition,this study extended these theoretical constructs to investigate differences in RPA and ISE among potential audience segments,providing practitioners with applicable insights for designing effective flood prevention and risk management *** of data from 716 residents in south Louisiana revealed a statistically strong relationship between RPA and *** research also identified specific audience segments that would benefit from an increase in RPA and ISE concerning *** meaningful findings infonn a discussion of the theoretical and practical implications of the relationship between RPA and ISE and guide future disaster preparation campaigns and policies.

关键词： Communication campaign Disaster preparation Flood victims Information-seeking efficacy Pluvial flood Risk perception attitude

MCNP-ORIGEN耦合通用程序(MOCUP) 的基准验证与实用化(英文)

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核动力工程 2003年第4期24卷 332-337页

作者：王侃 TPLou E greenspan J Vujic 清华大学工程物理系北京100084 美国加州大学伯克利分校核工程系 ca94720

本文的目的是将MOCUP程序实用化,以用于燃耗分析。选取了2个资料完整的基准问题以验证MOCUP程序本身和应用方法。一个基准题是压水堆的栅元燃耗问题(含3种状况);另一个是快堆的燃耗问题。适当选取程序的有关参数后,将MOCUP的计算结果同... 详细信息

本文的目的是将MOCUP程序实用化,以用于燃耗分析。选取了2个资料完整的基准问题以验证MOCUP程序本身和应用方法。一个基准题是压水堆的栅元燃耗问题(含3种状况);另一个是快堆的燃耗问题。适当选取程序的有关参数后,将MOCUP的计算结果同实验结果和/或其它程序计算结果相比较,可得如下结论:①除极个别特例外,MOCUP程序计算得到的同位素成分结果处于其它程序计算结果的范围之内;②与实验测量数据相比,MOCUP程序计算得到的锕系元素浓度的误差均小于11%,绝大多数小于5%;裂变产物浓度的误差小于10%,除 149Sm之外;③MOCUP程序计算得到的反应性随燃耗变化的结果与所报告的其它结果吻合很好。

关键词：燃耗分析基准题目 MOCUP